Method and device for determining concentration of target gas within sample gas

Abstract

Methods, devices, and systems are provided for determining a concentration of a target gas in a sample gas. An example method of preparing a replaceable test material for detecting a target gas in a sample gas can include preparing a solution including a solute and a solvent, wherein the solute includes o-bitoluidine; introducing a test material substrate into the prepared solution for a certain period of time; and removing at least a portion of the solvent from the test material substrate such that the test material substrate includes at least a portion of the o-bitoluidine, and thereby forming a replaceable test material for detecting the target gas in the sample gas.

Description

Technical Field

[0001] The disclosed embodiments relate generally to determining the concentration of a target gas within a sample gas, and more particularly to determining the concentration of nitric oxide (NO) within a sample gas using a disposable test material in a care setting or medical environment. Background Art

[0002] Applicants have recognized a number of deficiencies and technical problems associated with conventional systems, devices, and methods for determining the concentration of a target gas within a sample gas, particularly in a medical environment. Through applied effort, ingenuity, and innovation, many of these recognized problems have been addressed by developing solutions included in the disclosed embodiments, many examples of which are described in detail herein. Summary of the invention

[0003] In general, various embodiments of the disclosure provided herein may provide solutions to problems and needs in the art that have not been fully recognized, appreciated, or addressed by current technology used to determine the concentration of a target gas in a sample gas. According to some embodiments of the present disclosure, an example method of preparing a replaceable test material for determining the concentration of a target gas in a sample gas is provided. In some embodiments, the method may include: preparing a solution including a solute and a solvent, wherein the solute includes o-tolidine; introducing a test material substrate to the prepared solution for a certain period of time; and removing at least a portion of the solvent from the test material substrate so that the test material substrate includes at least a portion of the o-tolidine and thereby forming a replaceable test material for determining the concentration of a target gas in the sample gas.

[0004] In some embodiments, removing at least the portion of the solvent from the test material substrate may include evaporating the solvent (e.g., ethanol). In some embodiments, removing at least the portion of the solvent from the test material substrate may include applying absorbent paper to the test material substrate. In some further embodiments, removing at least the portion of the solvent from the test material substrate may include exposing the test material substrate to a nitrogen gas flow.

[0005] In some embodiments, the solvent may include ethanol. In some further embodiments, the solvent may include water.

[0006] In some embodiments, the time period for introducing the test material substrate into the prepared solution may be a minimum of about 30 seconds.

[0007] In some embodiments, the test material substrate comprises low speed test paper.

[0008] According to some embodiments of the present disclosure, an example method for determining the concentration of a target gas in a sample gas is further provided. In some embodiments, the method may include contacting a replaceable test material with the sample gas, wherein at least a portion of the sample gas is the target gas, and wherein the replaceable test material includes o-tolidine; identifying a color of the replaceable test material; and determining the concentration of the target gas in the sample gas based at least in part on the identified color of the replaceable test material.

[0009] In some embodiments, determining the concentration of the target gas in the sample gas may include: determining the concentration of an oxidized derivative of the target gas; and correlating the determined concentration of the oxidized derivative with the concentration of the target gas. In some further embodiments, the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide.

[0010] In some embodiments, contacting the replaceable test material with the sample gas may include exposing the replaceable test material to a sample gas flow. In some further embodiments, the replaceable test material is disposed in a gas detection device, and exposing the replaceable test material to the sample gas flow may include directing the sample gas flow toward the replaceable test material in the gas detection device. In some further embodiments, the sample gas may include the target gas, and after contacting the replaceable test material with the sample gas, the replaceable test material changes color based at least in part on the presence of the target gas. In still further embodiments, the identified color of the replaceable test material may be blue, green, or a combination thereof.

[0011] According to some embodiments of the present disclosure, an example reusable gas detection device for determining the concentration of a target gas in a sample gas is provided. In some embodiments, the example reusable gas detection device may include: a replaceable test material configured to change color based at least in part on the presence of a target gas in the sample gas or the presence of an oxidized derivative of the target gas in the sample gas, wherein the replaceable test material includes o-tolidine; and a controller configured to determine the concentration of the target gas.

[0012] In some embodiments, the reusable gas detection device may further include an imaging device, and the controller may be configured to determine the concentration of the target gas based at least in part on correlating the color of the replaceable test material in one or more images of the replaceable test material captured by the imaging device with the concentration of the target gas.

[0013] In some embodiments, the controller can be configured to determine the concentration of the target gas based at least in part on determining a concentration of an oxidized derivative of the target gas.

[0014] In some embodiments, the reusable gas detection device may include: an oxidation chamber including an oxidant, wherein the oxidant oxidizes at least a portion of the target gas in the sample gas into an oxidized derivative of the target gas before the sample gas reaches the replaceable test material. In some further embodiments, the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide. In still further embodiments, the reusable gas detection device may include: an integrated display configured to present the results of the determined concentration of the nitric oxide in the sample gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Having thus generally described the present disclosure, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale. The components illustrated in the drawings may or may not be present in certain embodiments described herein. Some embodiments may include fewer (or more) components than those components shown in the drawings according to example embodiments of the present disclosure.

[0016] Figure 1 An exploded view of an example gas detection device is illustrated according to some example embodiments described herein.

[0017] Figure 2 Illustrated is a schematic block diagram showing example components of a colorimeter reader according to some example embodiments described herein.

[0018] Figure 3 Illustrated is a schematic block diagram showing example components of a controller according to some example embodiments described herein.

[0019] Figure 4 Depicted is a flow chart illustrating an example method of preparing a displaceable test material for determining a concentration of a target gas within a sample gas, according to some example embodiments described herein.

[0020] Figure 5 Depicted is a flow chart illustrating an example method for determining a concentration of a target gas in a sample gas according to some example embodiments described herein. DETAILED DESCRIPTION

[0021] Example embodiments of the present disclosure will now be more fully described hereinafter with reference to the accompanying drawings, in which some but not all embodiments of the present disclosure are shown. Indeed, embodiments of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will satisfy applicable legal requirements. Throughout, like reference numerals refer to like elements.

[0022] Various example embodiments address technical issues associated with determining the concentration of a target gas contained within a sample gas. As will be appreciated by those skilled in the art, there are many example scenarios in which a user may seek to determine the concentration of a target gas within a sample gas. For example, there are many environmental and health-related scenarios in which determination of the concentration of a target gas, such as nitric oxide (NO), in a sample gas may be desirable or necessary. However, some target gases, such as nitric oxide, may be particularly difficult to measure, particularly in medical scenarios, due to rapid chemical reactions with a wide range of molecules.

[0023] The use of nitric oxide in various medical treatments has become extensive. The presence of nitric oxide in biomaterials has been linked to various beneficial effects in health situations, particularly due to the effect that nitric oxide has at the cellular level. For example, nitric oxide has been utilized in wound healing therapy to achieve improvements in the inflammatory response to damaged cells, cell growth and regrowth, the formation of new blood vessels carried out by collagen formation, and the formation of microbial colonies. Nitric oxide has also been shown to show improvements in anticancer activity in vivo. In addition, nitric oxide has been utilized in respiratory applications and cardiovascular applications that show improvements in the operation of these human systems. Significant research continues to be performed on the development and evaluation of nitric oxide donors (such as dendrimers, metal-organic frameworks (MOFs), micelles, inorganic nanoparticles (NPs) and gels), which are used to deliver nitric oxide to various biological systems that can benefit from the increase of nitric oxide. Due to the many physiological and pathological advantages of nitric oxide, the regulation of nitric oxide levels in various tissues can have significant therapeutic value. Further, regulation of nitric oxide levels may necessarily involve accurate measurement of nitric oxide in various sample gases.

[0024] Many example methods for measuring nitric oxide are costly, inaccurate, unreliable, unsuitable for medical or point-of-care applications, and / or difficult to manage. Chemiluminescence, for example, utilizes the chemiluminescent properties of nitric oxide when reacting with ozone to determine the amount of nitric oxide in a particular substance based on light output. Chemiluminescence can generally be used in laboratory and / or hospital settings, however, the expense of chemiluminescence may be too high, so that the use of chemiluminescent technology may be limited to research situations, such as in large-scale hospitals and universities. In addition, the detection time is long and the process is complicated, so that a highly trained operator may be necessary to perform the test. Further, the detection system must be periodically calibrated to obtain accurate results.

[0025] Gas chromatography can use analytical chemistry for separating and analyzing compounds that can evaporate without decomposition. Gas chromatography can be better suited for laboratory, environmental and / or industrial applications, and is not easily performed for individuals or patients in a healthcare setting. In addition, gas chromatography can be overly expensive, and similar to chemiluminescence, the detection time is long and the process is complicated, so that a highly trained operator may be necessary to perform the test. Further, the detection system must be periodically calibrated to obtain accurate results.

[0026] Electrochemical sensors can generate an electrical current from the energy released by a spontaneous redox reaction. However, electrochemical sensors can be difficult to calibrate and operate, so that a highly trained operator may be necessary to manage the testing process. Additionally, the expense of using electrochemical sensors to detect nitric oxide can be significant.

[0027] Spectral absorption can use spectral techniques to measure the absorption of radiation as a function of the frequency of the wavelength of the incident light. Due to the interaction of the incident light with the sample gas, the concentration of nitric oxide can be detected. However, spectral absorption may be better suited for laboratory and / or environmental applications and is not easy to perform for individuals or patients in a healthcare environment. In addition, the test duration of spectral absorption may be long. Further, the cost per test of performing spectral absorption may be excessively expensive, and the test execution process is complex, so that a highly trained operator may be necessary to perform the test and periodically calibrate the test equipment.

[0028] Various embodiments of the present disclosure provide methods and devices for determining the concentration of a target gas (such as nitric oxide) in a sample gas. The inventors have determined that it would be desirable and advantageous to be able to more easily and efficiently determine the concentration of nitric oxide in a sample gas. Due to the example embodiments described herein and in some examples, the effectiveness and ease of use of a gas detection device capable of detecting nitric oxide can be greatly improved. For example, in some embodiments, although the gas detection device can be reusable, the measuring components (e.g., replaceable test materials) of the gas detection device can be disposable (i.e., replaceable), so that the test material is used only once, thereby reducing the possibility of exposing the patient to any possible contamination from a previous patient. In addition, the cost per test of the sample gas may be low due to the replaceable test material, and the replaceable test material may not require periodic calibration for accurate operation due to prior use. These characteristics and additional features, functions and details are described below. Similarly, corresponding and additional embodiments are also described below.

[0029] Example devices of the present disclosure The disposable test material 105 of the present disclosure may be used in a variety of gas detection devices and is not limited to the gas detection devices described herein. Figure 1 , illustrates an example gas detection device 100 according to an example embodiment. Figure 1 As depicted in , the example gas detection device 100 can be configured to receive a sample gas 150, for example, via an inlet 101. The inlet 101 can be any hose, pipe, nozzle, or similar structure configured to receive the sample gas 150 from a gas source. The sample gas 150 can be any gas, fluid, and / or substance received from any such gas source. For example, the sample gas 150 can be received from a subject (such as a human subject), an environment, a machine, a cavity, a space, or other biological or environmental source. The source can be direct (e.g., by the subject exhaling directly into the inlet 101) or indirect (e.g., from a sample bag). The sample gas 150 can be composed of multiple gases and molecules.

[0030] In some embodiments, the sample gas 150 may potentially include a target gas 160A. The target gas 160A may include any gas, fluid, and / or substance from any source. The target gas 160A may be one or more gases for which the gas detector device 100 is configured to detect. For example, in some embodiments, the target gas 160A may be nitric oxide (NO). The target gas 160A may include a gas concentration within the sample gas 150. Gas concentration refers to the amount (e.g., mass, atoms, molecules, moles) of gas present in a certain volume at a certain time. The gas concentration for the target gas 160A may be measured as a ratio of the number of particles of the target gas 160A to the total number of particles in the sample gas 150. In some embodiments, the concentration measurement result may be expressed as a ratio such as parts per million (ppm) or parts per billion (ppb). In some embodiments, the replaceable test material 105 may be used to detect concentrations of target gas 160A and / or oxidized derivatives 160B of the target gas as low as 5 ppb.

[0031] like Figure 1 As depicted in , the example gas detection device 100 may include a replaceable test material 105. Although the gas detection device 100 itself may be reusable, the replaceable test material 105 is configured to be consumable (e.g., a one-time use, disposable, replaceable component). Figure 1As depicted in , the replaceable test material 105 can be disposed within the gas detection device 100, for example, within a flow of the sample gas 150 (e.g., the sample gas flow). The replaceable test material 105 can include any material that is configured to react with a stimulus (e.g., the target gas 160A or its oxidized derivative 160B) such that the replaceable test material 105 changes color when the replaceable test material 105 is exposed to the stimulus. In such embodiments, the replaceable test material 105 is a colorimetric indicator of the presence of the stimulus (e.g., nitric oxide or any oxidized derivative, such as nitrogen dioxide (NO2)). In other words, in some embodiments, the color and / or shade of the replaceable test material 105 can be an indicator of the concentration of the target gas 160A (e.g., or its oxidized derivative 160B) within the sample gas 150. For example, in some embodiments, the darker the shade of the color, the higher the concentration of the target gas 160A or its oxidized derivative 160B. For example, in some embodiments, different shades of blue, green, and / or turquoise may indicate different concentrations of the target gas 160A or its oxidized derivatives 160B. Or, for example, in some embodiments, yellow may indicate low concentrations and red may indicate high concentrations, with different colors based on various concentration ranges. Positioning the replaceable test material 105 near or within the sample gas stream may provide a more accurate measurement of the concentration of the target gas 160A or its oxidized derivatives 160B within the sample gas 150. Figure 4 An example method of preparing a replaceable test material 105 for determining the concentration of a target gas 160A in a sample gas 150 is further described.

[0032] like Figure 1 As further depicted in , the example gas detection device 100 may include a colorimeter reader 200. The colorimeter reader 200 may be any device including a sensing element and a computing component configured to determine the concentration of the target gas 160A and / or the oxidized derivative 160B of the target gas within the sample gas 150 based on the measurement results derived from the replaceable test material 105. For example, in Figure 2 An example block diagram of an example colorimeter reader 200 is provided in FIG. Figure 2, the colorimeter reader 200 may include an imaging device 215. The imaging device 215 may be any device, module, or other means configured to capture image data (e.g., one or more images of the replaceable test material 105). The imaging device 215 may include a lens, an image sensor (e.g., a charge coupled device sensor, a complementary metal oxide semiconductor sensor), and / or a communication circuit. In some embodiments, the imaging device 215 may be directed to capture image data of the replaceable test material 105. In some embodiments, the image sensor may be configured to capture a color image, thereby enabling the gas detection device 100 to determine the concentration of the target gas 160A and / or the oxidized derivative 160B of the target gas within the sample gas 150 based at least in part on the color of the replaceable test material 105. In some embodiments, the imaging device 215 may include: an onboard processor that supports, among other things, image processing functions.

[0033] like Figure 2 As depicted in FIG. 1 , the imaging device 215 may be electrically and communicatively connected to the controller 210, thereby enabling the imaging device 215 to transmit the captured image data to the controller 210 for further processing. Changes in the color of the replaceable test material 105 may be monitored and / or identified by the controller 210, such as with respect to Figure 5 For example, based at least in part on the image received from the imaging device 215, the controller 210 of the colorimeter reader 200 can determine the concentration of the target gas 160A and / or the oxidized derivative 160B of the target gas within the sample gas 150. Figure 3 An example controller 210 is further described.

[0034] Back to Figure 1 , the example gas detection device 100 may include an oxidation chamber 115. In some embodiments, as Figure 1 As depicted in , the oxidation chamber 115 can be disposed within the gas inlet 101 of the gas detection device 100. The oxidation chamber 115 can include one or more gas filters 116. The gas filter 116 can include any material, structure, or device or a combination of materials, structures, or devices configured to allow the sample gas 150 to flow through while substantially removing volatile organic compound (VOC) molecules and / or moisture contained in the sample gas 150. Non-limiting examples of the gas filter 116 can include cellulose acetate, polypropylene, paper, cotton, charcoal, cork, and other permeable materials. In some embodiments, a combination of materials can be utilized as the gas filter 116, for example, a first material can be utilized to remove VOCs and a second material can be utilized to remove moisture from the sample gas 150.

[0035] like Figure 1As further depicted in FIG. 1 , the exemplary oxidation chamber 115 of the gas detection device 100 may include an oxidant 120. For example, Figure 1 As depicted in , the first gas filter 116 can be disposed near the proximal end of the oxidation chamber 115, and the second gas filter 116 can be disposed near the end of the oxidation chamber 115, and the oxidant 120 can be disposed therebetween. The oxidant 120 can be any chemical, compound, material, or other substance that can easily transfer oxygen atoms to the target gas 160A in the sample gas 150. That is, before the sample gas 150 reaches the replaceable test material 105 disposed in the gas detection device 100, the oxidant 120 oxidizes at least part of the target gas 160A in the sample gas 150 into an oxidized derivative 160B of the target gas. For example, in an example in which nitric oxide is the target gas 160A, an oxidant 120 such as a metal oxide compound or potassium permanganate (KMnO4) can be used. As the nitric oxide molecules pass through the oxidation chamber 115, the oxidant can transfer oxygen atoms to them. In some embodiments, this oxidation results in an oxidized derivative nitrogen dioxide (NO2). Nitrogen dioxide can be more stable than nitric oxide and less prone to react with other chemical molecules. Accordingly, measuring the resulting concentration of nitrogen dioxide may provide an easier and more accurate representation of the amount of nitric oxide in the sample gas 150 than attempting to measure the concentration of nitric oxide directly.

[0036] like Figure 1As further depicted in , the example gas detection device 100 may optionally include: a housing 102 configured to receive a sample gas 150 via a gas inlet 101 and direct a flow of the sample gas 150 (e.g., a sample gas flow) toward a replaceable test material 105. The optional housing 102 may also be configured to receive and / or attach to a cover 103. A cover ring 104 (e.g., an O-ring) may surround an outer edge of the cover 103 to create an airtight seal between the cover 103 and a wall of the housing 102. The cover 103 may include a gas outlet opening 116 and a cover opening 114, the gas outlet opening 116 being arranged to receive the sample gas flow from the housing 102 and direct the sample gas flow through the cover opening 114 disposed opposite the gas outlet opening 116. The cover opening 114 can optionally be further configured to receive additional components, such as a replaceable test material 105, a squeeze rod 110 (e.g., to regulate gas flow), an air outlet ring 108 (e.g., an O-ring that creates an airtight seal between the squeeze rod 110 and the air outlet opening 116), and a lock 109 (e.g., to apply pressure to the cover 103 to ensure an airtight seal). The housing 102 can also be configured to provide a location for attachment (e.g., including one or more latching mechanisms, such as locks, latches, screws, or other mechanisms) to the colorimeter reader 200 so that a sensing device within the colorimeter reader 200 can monitor the replaceable test material 105 during operation.

[0037] Reference now Figure 3 , discloses an example controller 210 according to at least some example embodiments of the present disclosure. The controller 210 includes a processor 301, input / output circuitry 302, memory 303, communication circuitry 304, imaging device interface circuitry 305, and imaging processing circuitry 306. In some embodiments, the controller 210 is configured to perform and execute the operations described herein using one or more of the set of circuits 301, 302, 303, 304, 305, and / or 306.

[0038] Although the components are described with respect to functional limitations, it should be understood that specific implementations necessarily include the use of specific computing hardware. It should also be understood that in some embodiments, certain of the components described herein include similar or common hardware. For example, two sets of circuits may both utilize the use of the same processor(s), network interface(s), storage medium(s), etc. to perform their associated functions, such that duplicate hardware is not required for each set of circuits. Therefore, users of the term "circuitry" as used herein with respect to components of the apparatus described herein should be understood to include specific hardware configured to perform functions associated with specific circuits as described herein.

[0039] In particular, the term "circuit" should be broadly understood to include hardware and, in some embodiments, software for configuring hardware. For example, in some embodiments, a "circuit" includes a processing circuit, a storage medium, a network interface, an input / output device, and the like. Alternatively or additionally, in some embodiments, other elements of the controller 301 provide or supplement the functionality of other specific sets of circuits. For example, the processor 301 provides processing functionality to any one of a set of circuits in some embodiments, the memory 303 provides storage functionality to any one of a set of circuits, the communication circuit 304 provides network interface functionality to any one of a set of circuits, and the like.

[0040] In some embodiments, the processor 301 (and / or a coprocessor, or any other processing circuitry assisting the processor or otherwise associated with the processor) communicates with the memory 303 via a bus for passing information between components of the controller 210. In some embodiments, for example, the memory 303 is non-transient and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory 303 includes or embodies an electronic storage device (e.g., a computer-readable storage medium) in some embodiments. In some embodiments, the memory 303 is configured to store information, data, content, applications, instructions, etc., for enabling the controller 210 to implement various functions according to example embodiments of the present disclosure.

[0041] The processor 301 can be embodied in a variety of different ways. For example, in some example embodiments, the processor 301 includes one or more processing devices configured to execute independently. Additionally or alternatively, in some embodiments, the processor 301 includes one or more processors configured in series via a bus to implement independent execution of instructions, pipelining, and / or multithreading. The use of the terms "processor" and "processing circuit" should be understood to include a single-core processor, a multi-core processor, multiple processors within the controller 210, and / or one or more remote or "cloud" processors external to the controller 210.

[0042] In an example embodiment, the processor 301 is configured to execute instructions stored in the memory 303 or otherwise accessible to the processor. Alternatively or additionally, the processor 301 is configured in some embodiments to execute hard-coded functionality. Thus, whether configured by hardware methods, software methods, or a combination thereof, the processor 301 represents an entity (e.g., physically embodied in a circuit) that is capable of performing operations according to embodiments of the present disclosure when configured accordingly. Alternatively or additionally, as another example in some example embodiments, when the processor 301 is embodied as an executor of software instructions, the instructions specifically configure the processor 301 to: when such instructions are executed, perform the algorithm embodied in the specific operations described herein.

[0043] As a specific example embodiment, the processor 301 is configured to perform various operations associated with utilizing various sensors and devices to determine the concentration of the target gas 160A in the sample gas (e.g., the sample gas 150). In some embodiments, the processor 301 includes hardware, software, firmware, and / or a combination thereof to receive an image of a test material (e.g., the displaceable test material 105) from an imaging device (e.g., the imaging device 215), wherein the test material is located within the sample gas flow, and wherein the color of the test material is related to the concentration of the target gas (e.g., the target gas 160A and / or its oxidized derivatives 160B). Additionally or alternatively, in some embodiments, the processor 301 includes hardware, software, firmware, and / or a combination thereof to determine the concentration of the target gas 160A and / or its oxidized derivatives 160B based at least in part on the color of the test material (e.g., the displaceable test material 105).

[0044] In some embodiments, controller 210 includes: input / output circuit 302, which provides output to the user, and receives the indication of user input in some embodiments. In some embodiments, input / output circuit 302 communicates with processor 301 to provide this functionality. Input / output circuit 302 may include one or more user interfaces (e.g., user interface), and in some embodiments includes a display, which includes (one or more) interfaces presented as web user interface, application user interface, user equipment, back-end system, etc. Processor 301 and / or input / output circuit 302 including processor can be configured to: control one or more functions of one or more user interface elements by computer program instructions (e.g., software and / or firmware) stored on a memory (e.g., memory 303, etc.) accessible to the processor. In some embodiments, input / output circuit 302 includes or utilizes user-oriented applications to provide input / output functionality to client devices and / or other displays associated with the user.

[0045] In some embodiments, the controller 210 includes a communication circuit 304. The communication circuit 304 includes any of the following means (such as a device or circuit) embodied in hardware or a combination of hardware and software: the device is configured to receive data from a network and / or any other device, circuit or module in communication with the controller 210 and / or transmit data to a network and / or any other device, circuit or module in communication with the controller 210. In this regard, for example, in some embodiments, the communication circuit 304 includes a network interface for implementing communication with a wired or wireless communication network. Additionally or alternatively, in some embodiments, the communication circuit 304 includes one or more network interface cards, antennas, buses, switches, routers, modems, and any other devices supporting hardware, firmware and / or software, or suitable for implementing communication via one or more communication networks. Additionally or alternatively, the communication circuit 304 includes a circuit for interacting with (one or more) antennas and / or other hardware or software to transmit signals via (one or more) antennas or handle the reception of signals received via (one or more) antennas. In some embodiments, communication circuitry 304 enables transmission of data to and / or reception of data from client devices in communication with controller 210 .

[0046] The imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that support various functionalities associated with command and control of an imaging device (e.g., imaging device 215) of a colorimeter reader (e.g., colorimeter reader 200). For example, in some embodiments, the imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that receive, decode, and / or otherwise process or pre-process captured image data. Additionally or alternatively, in some embodiments, the imaging device interface circuit 305 includes hardware, software, firmware, and / or combinations thereof that store and / or otherwise cache image data for subsequent use, retrieval, transmission, and / or other processing. In some embodiments, the imaging device interface circuit 305 includes a separate processor, a specially configured field programmable gate array (FPGA), or a specially programmed application specific integrated circuit (ASIC).

[0047] In an example embodiment, the imaging device interface circuit 305 may further include hardware, software, firmware, and / or a combination thereof for commanding and controlling the imaging device. Various commands may be transmitted to the imaging device to configure the imaging device based on the received image data. For example, the imaging device interface circuit 305 may be configured to monitor and adjust exposure time, ISO sensitivity, white balance, shutter speed, gain, frame rate, dynamic range, bit depth, and other parameters related to the quality of the image data.

[0048] The image processing circuit 306 includes hardware, software, firmware, and / or combinations thereof that support various functionalities associated with processing captured image data received from the image sensor. In an example embodiment, the image processing circuit 306 may perform image processing techniques to prepare the captured image data for further processing by, for example, removing optical noise, emphasizing features such as edges, determining features that accompany identification of an object of interest, calculating feature values ​​that accompany identification of an object represented by the captured image data, and other similar techniques known to those skilled in the art. In some embodiments, the image processing circuit 306 may utilize image processing techniques on the processed captured image data to identify an object of interest, such as the test paper 306 and similar objects of interest. In some embodiments, the image processing circuit 306 may utilize further image processing techniques to identify the color of an object of interest according to a related color space (e.g., red green blue (RGB), hue saturation value (HSV), hue brightness saturation (HLS), brightness blue projection red projection (YUV, YCbCr), cyan magenta yellow (CMY)). The determined color of the object of interest (eg, displaceable test material 105) may be compared to properties of the object of interest to determine the concentration of the target gas (eg, target gas 160A and / or its oxidized derivatives 160B).

[0049] Additionally or alternatively, in some embodiments, one or more of the sets of circuits 301-306 are combinable. Additionally or alternatively, in some embodiments, one or more of the sets of circuits perform some or all of the described functionality associated with another component. For example, in some embodiments, one or more of the sets of circuits 301-306 are combined into a single module embodied in hardware, software, firmware, and / or a combination thereof. Similarly, in some embodiments, one or more of the sets of circuits (e.g., imaging device interface circuit 305) are combined so that processor 301 performs one or more of the operations described above with respect to each of these circuits individually.

[0050] Additionally or alternatively, in some embodiments, one or more of the sets of circuits 301-306 are combinable. Additionally or alternatively, in some embodiments, one or more of the sets of circuits perform some or all of the described functionality associated with another component. For example, in some embodiments, one or more of the sets of circuits 301-306 are combined into a single module embodied in hardware, software, firmware, and / or a combination thereof. Similarly, in some embodiments, one or more of the sets of circuits (e.g., imaging device interface circuitry 305 and / or image processing circuitry 306) are combined so that processor 301 performs one or more of the operations described above with respect to each of these circuits individually.

[0051] Example Methods of the Disclosure refer to Figure 4 and 5 , respectively illustrate an example method for preparing a test material for determining the concentration of a target gas (e.g., nitric oxide) in a sample gas and using such a test material to determine the concentration of a target gas (e.g., nitric oxide) in a sample gas. That is, Figure 4 and Figure 5 A flow chart is illustrated including a series of steps for preparing a replaceable test material and determining the concentration of a target gas 160A (eg, nitric oxide) in a sample gas 150 (eg, using a gas detection device 100 and / or replaceable test material 105 as described above).

[0052] Reference now Figure 4 , illustrates an example method 400 for preparing a replaceable test material (e.g., replaceable test material 105) for determining the concentration of a target gas in a sample gas (e.g., sample gas 150). At block 402, the example method 400 includes preparing a solution including a solute and a solvent, wherein the solute includes o-tolidine. In an example embodiment, o-tolidine, which may also be referred to as 3,3'-dimethylbenzidine or 4,4'-diamino-3,3'-dimethylbiphenyl, may be present in powder form and dissolved in and / or mixed with ethanol and / or water. In an example embodiment, approximately 5-20 mg of o-tolidine may be mixed with 1-5 mL of CH3CH2OH,>98%. In another example embodiment, approximately 5-20 mg of o-tolidine may be mixed with 1-5 mL of CH3CH2OH,>98% and 1-5 mL of water.

[0053] Continue to refer Figure 4 At block 404, the example method 400 includes introducing the test material substrate into the prepared solution for a period of time. For example, in some embodiments, the test material substrate (such as a low-speed test paper) may be immersed in the solution prepared at block 402 for a minimum of 30 seconds. In some further embodiments, the test material substrate may be immersed in the solution prepared at block 402 for approximately 30-120 seconds. The low-speed test paper may refer to a test material substrate having a tighter fibrous condition, wherein the pores have a smaller diameter than a typical test paper (e.g., a normal speed test paper). Once prepared as a replaceable test material 105, such a low-speed test paper may provide a more uniform distribution of the solute (e.g., o-tolidine) once dried, and allow the sample gas 150 to pass slowly through the test paper, thereby achieving a more complete reaction of the applied solute with the target gas 160A (or its oxidized derivative 160B) (if any) present in the sample gas 150.

[0054] like Figure 4 As further illustrated in FIG. 4 , at block 406, the example method 400 includes: removing at least a portion of the solvent from the test material substrate, so that the test material substrate includes at least a portion of ortho-tolidine, thereby forming a replaceable test material (e.g., replaceable test material 105) for determining the concentration of a target gas (e.g., target gas 160A) in the sample gas 150. For example, removing at least a portion of the solvent from the test material substrate may include: applying absorbent paper and / or wrapping the test material substrate with absorbent paper (e.g., blotting paper). In some embodiments, the absorbent paper is contacted with the test material substrate for approximately 30-120 seconds. Additionally or alternatively, removing at least a portion of the solvent from the test material substrate may include: blowing an inert gas, such as nitrogen, on the test material substrate. That is, the test material substrate may be exposed to a nitrogen gas flow for a period of time, such as approximately 30-120 seconds. The prepared replaceable test material 105 may be stored in a light-shielding package at approximately -20°C to below 4°C. Additionally or alternatively, the prepared disposable test material 105 may be sealed in a package until use.

[0055] Reference now Figure 5 , illustrates an example method for determining a concentration of a target gas (e.g., target gas 160A) in a sample gas (e.g., sample gas 150). At block 502, the example method 500 includes contacting a replaceable test material (e.g., replaceable test material 105) with a sample gas (e.g., sample gas 150). In this example, the replaceable test material 105 includes o-tolidine, and at least a portion of the sample gas 150 is the target gas 160A. The placement of the replaceable test material 105 may enable the sample gas 150 containing the target gas 160A to interact with the replaceable test material 105. For example, contacting the replaceable test material 105 with the sample gas 150 may include exposing the replaceable test material 105 to a flow of the sample gas 150 (e.g., a sample gas flow). In a non-limiting example, the replaceable test material 105 may be disposed in a gas detection device, and exposing the replaceable test material 105 to the sample gas flow may include directing the sample gas flow toward the replaceable test material 105 in the gas detection device.

[0056] In some embodiments, determining the concentration of the target gas 160A in the sample gas 150 may optionally include initially determining the concentration of an oxidized derivative 160B of the target gas and correlating the determined concentration of the oxidized derivative 160B with the concentration of the target gas 160A. For example, in instances where nitric oxide is the target gas 160A, the sample gas 150 may be subjected to an oxidation chamber 115 and / or exposed to an oxidant 120 to transfer oxygen atoms to nitric oxide molecules, thereby obtaining the oxidized derivative 160B nitrogen dioxide (NO2). Nitrogen dioxide may be more stable and less reactive to other chemical molecules than nitric oxide. Accordingly, measuring the resulting concentration of nitrogen dioxide may provide an easier and more accurate representation of the amount of nitric oxide in the sample gas 150 than attempting to directly measure the concentration of nitric oxide.

[0057] Continue to refer Figure 5 At block 504, the example method 500 includes identifying a color of the replaceable test material 105. For example, in some embodiments where the target gas 160A is present in the sample gas 150, the replaceable test material 105 may be configured to change color and / or color tint based at least in part on the presence of the target gas 160A and / or an oxidized derivative 160B of the target gas, such as described herein with respect to Figure 4 As described. For example, in some embodiments, in the portion(s) of the replaceable test material 105 contacted by the sample gas flow, the replaceable test material 105 may change from white or beige to a shade of blue, green and / or cyan and / or blue, green and / or cyan, such that the identified color of the replaceable test material 105 is blue, green and / or cyan. For example, in a non-limiting example, ortho-tolidine present in or on the surface of the replaceable test material 105 may react with nitrogen dioxide (e.g., an oxidized derivative 160B of nitric oxide) present in the sample gas 150 to form nitroso-ortho-toluidine. In doing so, the portion(s) of the replaceable test material 105 contacted by the sample gas flow may initially turn yellow-orange. In instances where such replaceable test material 105 is further exposed to, for example, air, the color may subsequently change to one or more shades of blue, green, and / or turquoise for a period of time (during which the concentration of target gas 160A and / or oxidized derivatives 160B may be determined) due to the presence of moisture (e.g., H2O) in the air. In some instances, the replaceable test material 105 may further change to a darker color, such as brown, gray, and / or black.

[0058] In another non-limiting example where water is included as at least a portion of the solvent, o-tolidine and water present in or on the surface of the replaceable test material 105 can react with nitrogen dioxide (e.g., an oxidized derivative of nitric oxide 160B) present in the sample gas 150 to form nitro-o-toluene. In doing so, the portion(s) of the replaceable test material 105 contacted by the sample gas stream can initially turn one or more shades of blue, green, and / or turquoise for a period of time, at which time the concentration can be determined. In some instances, the replaceable test material 105 can further turn a darker color, such as brown, gray, and / or black, when exposed to air.

[0059] Although it is possible to manually and / or visually determine the color and / or color tint of the replaceable test material 105, in some embodiments, the controller 210 can utilize various hardware and software (e.g., image processing circuit 306) to determine the color and / or tint of the replaceable test material 105. In some embodiments, the controller (e.g., controller 210) receives an image of the replaceable test material (e.g., replaceable test material 105) from an imaging device (e.g., imaging device 215). In some embodiments, the captured image data can be received by the controller 210 at regular intervals, such as based on the frame rate of the imaging device 215. In some embodiments, the image data can be received at the request of the controller 210. The image data can be transmitted in any format, such as an image format (e.g., JPEG, PNG, GIF, BMP, TIFF, etc.) and / or a video format (e.g., MP4, AVI, MKV, MOV, WMV, etc.). Similarly, the image data can be transmitted using any transmission standard (e.g., H.264, MPEG-4, G.265, HEVC, VP8, VP9, ​​etc.). The processor 301 can utilize various hardware and / or software components (e.g., imaging device interface circuitry 305) to receive image data and decode the received image data. In some embodiments, the controller 210 can utilize image processing algorithms and techniques to identify the replaceable test material 105 and determine the color and / or color shade of the replaceable test material 105.

[0060] like Figure 5As further illustrated in FIG. 5 , at block 506, the example method 500 includes determining a concentration of the target gas 160A in the sample gas 150 based at least in part on the identified color of the replaceable test material 105. For example, in some embodiments, the color and / or hue of the replaceable test material 105 as identified at block 504 may change based on the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B, such that the color and / or hue may be correlated with the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B. In some embodiments, a controller (e.g., the controller 210) may determine the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B based at least in part on the color and / or hue of the replaceable test material 105. That is, in some embodiments, the color and / or color hue of the replaceable test material 105 may be indicative of the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B. For example, in the presence of the target gas 160A and / or the oxidized derivative 160B of the target gas, the replaceable test material 105 may turn blue, green, and / or cyan, however, a light shade of blue, green, and / or cyan may represent a concentration below 1%, a slightly darker shade of blue, green, and / or cyan may represent a concentration between 1% and 2%, and so on. In another non-limiting example, red may represent a concentration below 1%, orange may represent a concentration between 1% and 2%, yellow may represent a concentration between 2% and 4%, and so on. The color and / or hue of the associated concentration may be determined prior to operation and may be input to the controller 210 as a configuration or operating parameter. Additionally, the color and / or hue of the associated concentration may be learned, such as by training using known target gases, oxidized derivatives, and / or user input.

[0061] In some embodiments, the controller 210 may optionally consider additional parameters when determining the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B. For example, the physical characteristics of the test environment and / or the replaceable test material 105 may affect the determined concentration(s). The physical characteristics may include the temperature, humidity, and / or pressure of the test environment, the size and position of the replaceable test material 105, and the like. The additional parameters may also include the gas flow rate of the sample gas 150. In some embodiments, the molecular composition of the target gas 160A, the oxidized derivative of the target gas 160B, and / or the sample gas 150 may also be considered when determining the concentration of the target gas 160A and / or the oxidized derivative of the target gas 160B within the sample gas 150.

[0062] Therefore, a specific embodiment of the subject matter has been described. Although this specification contains many specific implementation details, these should not be understood as limitations on the scope of any invention or content that can be claimed, but should be understood as descriptions of features that are dedicated to a specific embodiment of the present disclosure. Other embodiments are within the scope of the appended claims. Certain features described herein in the context of a separated embodiment can also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment can also be implemented separately or in any suitable sub-combination in multiple embodiments. In addition, although the features can be described above as acting in certain combinations and even initially claiming the features, one or more features from the combination can be deleted from the claimed combination in some cases, and the claimed combination can be guided to a sub-combination or a variation of the sub-combination.

[0063] Similarly, although operation or step is described in a specific order in the accompanying drawings, this should not be understood as requiring that such operation or step can be performed in the specific order shown or in a sequential order, or requiring that all illustrated operations or steps are performed, to achieve the desired result, unless described in another way. In some cases, multitasking and parallel processing can be advantageous. In addition, the separation of various system components in the above-described embodiment should not be understood as requiring this separation in all embodiments, and it should be understood that the described program components and system generally can be integrated together in a single software product or be packaged in a plurality of software products. For the purpose of the depicted embodiment, any operation step shown with dotted lines in one or more flow charts illustrated herein is optional.

[0064] In some cases, the actions recited in the claims can be performed in a different order and still achieve the desired results. Additionally, the processes depicted in the accompanying drawings do not necessarily require the particular order or sequential order shown to achieve the desired results, unless otherwise described. In certain implementations, multitasking and parallel processing may be advantageous.

[0065] Overview of terminology The following explanations of terms are provided to better describe the present disclosure and guide those skilled in the art in the practice of the present disclosure.

[0066] As used herein, the term "comprising" means including, but not limited to, and should be interpreted in the manner in which it is typically used in a patent context. The use of broader terms such as including, comprising, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and composed essentially of.

[0067] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases are not necessarily referring to the same embodiment.

[0068] As used herein, the terms "illustrative," "example," "exemplary," and the like are used to mean "serving as an example, instance, or illustration" without indicating a level of quality. Any implementation described herein as "exemplary" or "example" is not necessarily to be construed as preferred or advantageous over other implementations.

[0069] The terms "about," "approximately," "generally," "substantially," and the like, when used with numbers, may mean the specific number or, alternatively, a range close to the specific number as understood by those skilled in the art and may be used to refer to being within manufacturing and / or engineering design tolerances for the corresponding materials and / or elements, as would be understood by those skilled in the art, unless otherwise indicated.

[0070] If the specification states that a component or feature "may", "can", "could", "should", "will", "preferably", "likely", "typically", "optionally", "for example", "often", or "might" (or other such language) be included or have a property, that particular component or feature does not have to be included or have that property. Such a component or feature may optionally be included in some embodiments, or it may be excluded.

[0071] If the specification presents a list, it should be understood that each individual element of the list and each combination of components of the list is a separate embodiment unless otherwise stated. For example, "1, 2, 3, 4, and 5" encompasses, among many embodiments: 1; 2; 3; 1 and 2; 3 and 5; 1, 3, and 5; and 1, 2, 4, and 5.

[0072] The term "plurality" refers to two or more items.

[0073] The term "collection" refers to a collection of one or more items.

[0074] The term "or" is used herein in both the alternative and conjunctive senses, unless indicated otherwise.

[0075] Unless otherwise explained, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present disclosure belongs. Although methods and materials similar or equivalent to the methods and materials described herein can be used in the practice or testing of the present disclosure, suitable methods and materials are described herein. Materials, methods and examples are illustrative only and are not intended to be limiting unless otherwise indicated. Other features of the present disclosure become apparent from the detailed description and claims.

[0076] in conclusion The disclosure of the advantages of the teaching presented in the above description and the associated drawings will be known to those skilled in the art of the disclosure as described herein. Many modifications and other embodiments of the disclosure set forth herein will be thought of. Therefore, it should be understood that the disclosure should not be limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the above description and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be appreciated that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, as may be set forth in some of the appended claims, it is also contemplated that elements and / or functional combinations different from the elements and / or functional combinations explicitly described above are used. Although specific terms are employed herein, they are used only in a general and descriptive sense, and not for the purpose of limitation.

[0077] Although the present disclosure has been particularly described in conjunction with specific examples, it is apparent that many alternatives, modifications and variations will become apparent to those skilled in the art in view of the above description. Therefore, it is conceivable that the appended claims will include any such alternatives, modifications and variations. That is, although various embodiments according to the principles disclosed herein have been shown and described above, those skilled in the art may make modifications thereof without departing from the spirit and teachings of the present disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations and modifications are possible and within the scope of the present disclosure. The disclosed embodiments are primarily directed to the detection of nitric oxide and / or its oxidized derivative nitrogen dioxide in a sample gas 150, however, those skilled in the art will recognize that this principle can be applied to any target gas 160A in any environment. For example, these techniques may also be used to detect other gases and / or volatile organic compounds (VOCs). Some example gases may include, but are not limited to, hydrogen sulfide (H2S), ammonia (NH3), carbon monoxide (CO), formaldehyde (HCHO), benzene (C6H6) and other similar gases. Alternative embodiments resulting from combining, integrating and / or omitting features of (one or more) embodiments are also within the scope of the present disclosure. Accordingly, the scope of protection is not limited by the description set forth above.

[0078] Additionally, section headings used herein are provided for consistency with the recommendations under 37 CFR 1.77 or to otherwise provide organizational cues. These headings shall not limit or characterize the invention(s) that may be set forth in any claim(s) that may issue from this disclosure.

Claims

1. A method for preparing a replaceable test material for determining the concentration of a target gas in a sample gas, comprising: preparing a solution comprising a solute and a solvent, wherein the solute comprises o-tolidine; introducing a test material substrate into the prepared solution for a certain period of time; and At least a portion of the solvent is removed from the test material substrate such that the test material substrate includes at least a portion of the o-tolidine and thereby forms a replaceable test material for determining a concentration of a target gas in the sample gas.

2. The method of claim 1, wherein removing at least the portion of the solvent from the test material substrate comprises applying absorbent paper to the test material substrate.

3. The method of claim 2, wherein removing at least the portion of the solvent from the test material substrate comprises exposing the test material substrate to a nitrogen gas flow.

4. The method of claim 1, wherein the solvent comprises ethanol. The method of claim 4 , wherein the solvent further comprises water.

6. The method of claim 1, wherein the time period is a minimum of approximately 30 seconds.

7. The method of claim 1, wherein the test material substrate comprises low speed test paper.

8. A method for determining the concentration of a target gas in a sample gas, the method comprising: contacting a displaceable test material with the sample gas, wherein at least a portion of the sample gas is the target gas, and wherein the displaceable test material comprises o-tolidine; identifying a color of the replaceable test material; and A concentration of the target gas in the sample gas is determined based at least in part on the identified color of the displaceable test material.

9. The method of claim 8, wherein determining the concentration of the target gas in the sample gas comprises: determining a concentration of an oxidized derivative of the target gas; And correlating the determined concentration of the oxidized derivative with the concentration of the target gas.

10. The method of claim 9, wherein the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide.

11. The method of claim 8, wherein contacting the replaceable test material with the sample gas comprises: The displaceable test material is exposed to a sample gas flow.

12. The method of claim 11, wherein the replaceable test material is disposed in a gas detection device, and exposing the replaceable test material to the sample gas flow comprises: A sample gas flow is directed toward a replaceable test material in the gas detection device.

13. The method of claim 12, wherein the sample gas includes the target gas and, after contacting the replaceable test material with the sample gas, the replaceable test material changes color based at least in part on the presence of the target gas.

14. The method of claim 13, wherein the identified color of the replaceable test material is blue, green, or a combination thereof.

15. A reusable gas detection device for determining the concentration of a target gas in a sample gas, the reusable gas detection device comprising: a disposable test material configured to change color based at least in part on the presence of a target gas in the sample gas or the presence of an oxidized derivative of the target gas in the sample gas, wherein the disposable test material comprises o-tolidine; as well as A controller is configured to determine a concentration of the target gas.

16. The reusable gas detection device of claim 15, further comprising: Imaging equipment, Wherein the controller is configured to determine the concentration of the target gas based at least in part on correlating a color of the replaceable test material in one or more images of the replaceable test material captured by the imaging device with the concentration of the target gas.

17. The reusable gas detection device of claim 15, wherein the controller is configured to determine the concentration of the target gas based at least in part on determining a concentration of an oxidized derivative of the target gas.

18. The reusable gas detection device of claim 17, further comprising: an oxidation chamber comprising an oxidant, The oxidant oxidizes at least a portion of the target gas in the sample gas into an oxidized derivative of the target gas before the sample gas reaches the replaceable test material.

19. A reusable gas detection device as claimed in claim 18, wherein the target gas is nitric oxide and the oxidized derivative is nitrogen dioxide.

20. The reusable gas detection device of claim 19, further comprising: An integrated display is configured to present the results of the determined concentration of the nitric oxide in the sample gas.

Images